Servers by jDrones

Digital MKS servos won't work with mRo Control Zero F7 and ArduPlane 4.0.5

I have been trying to do some bench testing with my new mRo Control Zero F7 and get it working. I was able to get Arduplane flashed to the microcontroller and I got some of the preliminary wiring done. However, I have not been able to get servos connected to the servo breakout board to work. I have external power going directly to the servo rail and I disabled the safety button in the parameters, but still no servo movement when armed in stabilize mode or other similar modes. I thought possibly the reason was because some of the board features might be disabled because I was connected to the supplied USB_OTG connector I used for flashing the firmware, but after making a new harness to connect a telemetry radio and power module, the servos still weren’t working. Again, I disabled the safety switch in the parameters 'BRD_SAFETYENABLE = 0" but still not working. Any peculiarities with the control zero that I don’t know about to get the servos working or is there a software bug somewhere?

Thanks for the help!


Good day, did you set correctly the parameters of the servo 1…etc on your parameters settings?

Below is the parameter file from the zero. I did set up the servo1 to be an aileron servo. Did you use a safety switch? The pwm output is displaying on Mission planner and responding to movements, but the servo is not moving.

params.param (17.9 KB)

i don’t use safety switch…

Not sure what we are doing differently. Could you upload your parameters file?

i will upload it later coz im in office…,

For sure thank you I appreciate the help!

can you try and provide the servos power from a different source to see if they work then. seems like they are not getting power. I normally provide servos power from a different source such as a separate BEC.

I’ve powered the servos with the same battery and power source. I have a pixracer and a pixhawk4mini that work fine with the power setup (7.4v Lipo through a 5V BEC). I don’t think that is likely to be the problem but I might get the multimeter out soon to see if that tells me anything

Are you using the same setup of your pixracer?
my servos are powered with a 5.30v sbec…,

Yes same bec power source, its the castle creations one

Update: I just tested it with a cheap nano servo and it worked. For some reason though, the MKS servo that I had working with the pixracer that I want to use is not working. I don’t know what is different, but if you know it would be appreciated if you could tell me. The same power supply is being used for both btw, a 5V castle creations BEC connected to a 7.4V lipo, so that doesn’t make sense to be the problem. Maybe its a difference in the duty cycle or some other type of configuration?

Update: when I have both the cheap micro servo and the MKS servo connected to the control zero, the cheap servo is responding normally and now the MKS servo is twitching around, but still not responding. I have tried changing the servo_rate parameter to 333 Hz but that hasn’t really helped any. Again the MKS servo seems to work completely fine with the pixracer, so I’m not sure if its a board problem or not. But then again the cheap servo works with the control zero. Still a mystery, any help would be appreciated

can you use notepad++ and see if there are any difference in param files between the two? post both the param files here for the zero and pixracer.

I have done that. I couldn’t find anything that stood out to me as being an issue. I tried changing the SERVO_RATE parameter around and it didn’t seem to matter on the pixracer and it didn’t seem to help on the zero.

pixracer.param (17.6 KB)
zero.param (17.9 KB)

Hi @Matt_C and @sdeal3

Just a tip on comparison of the parameters files, there is this little open source tool with great ui for windows called WinMerge which you might find easy to find diffs in files

Thanks for the tip. I did a compare of the two files and didn’t seem to find any notable differences. I have a feeling the issue is with some of the board hardware configuration that isn’t setup quite right

Servers by jDrones